please help. 21-28

21. If I am adding 2 numbers composed of 2 decimal digits in each byte, what bit in what register should I be concerned with for overflow conditions? Bit: in register: 22. Does the PIC16F876A have instruction pipelining? How many instructions can it pipeline? 23. In the RAM Data Register File area, what are the GPR data areas used for? 24. In the RAM Data Register File area, what are the SFR data areas used for? 25. How many basic instructions are available in the PIC16F876A? 26. What is a Tristate Gate? 27. What is an Open Collector Output? 28. In what order are addresses entered and retrieved off the Stack